The goal of the proposed fellowship is to prepare the applicant, Noa Krawczyk, for an independent research career focused on improving access to and effectiveness of services for the prevention and treatment of substance use disorders. To this end, the proposed fellowship consists of two complementary components: (1) A research project that aims to assess the relationship between receipt of opioid agonist therapy in specialty treatment settings and risk of opioid overdose and criminal justice involvement; and (2) a training plan composed of mentored research, didactic and informal training, experiential learning and professional development activities. The applicant will be supported by several resources at the Johns Hopkins Bloomberg School of Public Health and by a strong mentorship team with expertise in health services research, addiction medicine, the intersection of substance use and criminal justice, and advanced statistical methods. The research-training plan will allow Ms. Krawczyk to prepare for a research career by a) Learning and applying rigorous epidemiological and statistical methods; b) developing expertise in opioid use disorder treatment and services; and c) generating and disseminating scientific knowledge to inform public health practice. The proposed research project is of high